The overall mission of this core facility is to provide the necessary equipment and technical support for tissue culture to allow rigorous pursuit of the goals of the Program Project. The rationale for the proposed core is to establish a single laboratory, shared by members of the five groups (Projects 1 through 4 and Core C), which will alleviate duplications in costs of equipment, supplies, and salaries as well as further enhance scientific exchange between the participating labs. Establishment of this core facility will therefore save a substantial amount of research effort and costs for each of the component labs. Importantly, the core facility will also provide several services critical for the development of each project, including: a) Preparation and sterility testing of all cell culture media including specialized formulations and bulk reagents for preparative work. b) Screening serum lots for optimal growth promoting properties. Serum aliquoting and heat inactivation will also be performed. This service will allow for direct comparison of results between different groups without concern for differential serum effects on growth properties of cultured cell lines. c) Testing all cell lines for contamination including mycoplasma, bacteria and fungi. d) Routine maintenance of cell lines, including cell freezing and thawing. This will be an important service for investigators and will allow the rigorous recording of passage numbers. In addition, the facility will provide large scale preparation of cells for biochemical purposes. e) Maintenance of all tissue culture equipment as well as cleaning and periodic decontamination of equipment and facilities. Routine cleaning and decontamination greatly reduces the occurrence of spontaneous contamination detrimental to cell culture work.